PIKEVILLE A project to open a battery-manufacturing plant in Pikeville would be a watershed in efforts to diversify the beleaguered economy of Eastern Kentucky if it works as planned.

Government and business officials and executives from EnerBlu announced the project Friday in Pikeville.

The two-year-old company, currently based in Riverside, Calif., plans to build a $372 million plant in Pikeville to make lithium-titanate oxide batteries for transit buses and commercial and military vehicles. The company also makes products to support the electric grid and for use in military generators.

EnerBlu projected that the 1 million-square-foot plant on a reclaimed surface mine will open in 2020 and employ 875 people in its fourth year of operation. That would be in 2024 if construction of the plant goes as planned.

The company also plans to move its headquarters and research and development work to a 150,000-square-foot office in Lexington that is expected to open in early 2018. That office ultimately would have projected employment of 110.

The company’s total investment in Kentucky would be more than $400 million.

The project was a lightning bolt of good news in Pike County and the area, where the economy has been sapped by a sharp downturn in coal jobs.

More than 250 people packed the room at the Pikeville Expo Center for the announcement, and officials used words like historic and revolutionary to describe the project.

Many compared the potential for the plan to the economic impact Toyota has had in Central Kentucky with its Georgetown manufacturing plant.

“It’s a game-changer not only for Pikeville and Pike County, but for the entire region,” said state Sen. Ray Jones, a Pikeville Democrat who was at the announcement.

In the third quarter of 2011, there were 14,301 coal jobs in Eastern Kentucky. That number had plummeted to 3,896 in the third quarter of this year, according to the state Energy and Environment Cabinet.

The EnerBlu project could put many of the laid-off miners back to work and spark jobs at supplier plants, officials said.

Supporters also noted the potential for other benefits, including boosting the tax base; making it possible for people who have left the area for work to move back; and creating demand for housing.

“I think we’re just at the front end of something truly transformative for Eastern Kentucky,” said Republican Gov. Matt Bevin.

“We’ve dreamed about this day,” U.S. Rep. Hal Rogers, a Republican who represents Eastern and Southern Kentucky, said at the announcement.